TM MP5 misfires on semi but mostly not on auto

[mongo007]

I have a TM MP5 and on Semi it will fore 1/3 of the shoots great, 1/3 will go maybe 10 feet and the last 1/3 no BB is fired out. On Full auto it seems like about 9 of the 10 shoot great and 1 of the 10 dont fire. anyone know any solutions to this problem?


Thanks Munroe

[Styrak]

Has any work been done recently on the gun?
Could be a tappet plate/nozzle issue, or a worn/damaged hopup rubber.

[mongo007]

no work has been done, hopup looks fine as far as i can tell looking at it when i took out the barrel assembly. it still shoots the same as befor after i took it apart

[Styrak]

Even the slightest wear on the nozzle end of the hopup rubber can cause airseal issues, and misfeeds/jams.
Do you have a new rubber to test with?

[CDN_Stalker]

Sounds like the hop up unit needs to be checked out....

[mongo007]

ok sounds like i will check out the hop up more thoroughly. I will let you know what i find

thanks

Munroe

[mongo007]

I was reading up on how the action of firing a BB is so posed to go and i think something is off with my gun.

With no mag on and looking into the magwell at the tube the BB's go up i can see the chamber. I pull the trigger i see the nozzle move forward and then back... now to my understanding the nozzle should always be forward and then when you pull the trigger the nozzle will move back pick up a bb then mover forward and by that time the piston will have done its back then forward to shoot out the BB.

so am i right is that what could be causing the problems im having?

[mongo007]

Fixed the nozzle not it cycles properly on single fire like it should.
I took the hop up apart and everything looked fine.

BUT its still misfiring alot maybe even a bit more then before but i used mechbox.com and their videos and i put it back together exactly like i took it apart i was very careful to do so. I even took the mech box apart lubed it and cleaned it and it looks and sounds fine but i put it all together and i get misfeeding and double feeds and some good shots and some week shots I just cant seem to pin point the problem.

Does anyone have any help they can give or even Point out something someone else has said.

Any help is great

Thanks
Munroe

[Styrak]

I would say take it/send it to a gundoctor. They could pinpoint the problem in a fraction of the time.

[mongo007]

nearest gundoc is 3 hrs away for me

[CDN_Stalker]

An AEG nozzle never stops at the same point every time the trigger is pulled, even on semi. Ignore that myth, nozzle is least likey the cause of your problem. Any cracks on your hop up? Tappet plate worn where the nub of the sector gear hits it?

[mongo007]

Hop up looks perfect dont see any major ware or cracks or anything. should the tappet plate have a slight hollow where the nub would come in contact with it?

[CDN_Stalker]

Some do, depends on the hop up type for the gun and the mechbox type for the gun. Don't mean to sound vague, been a couple years since I was in my last mechbox, but more do have that recess, but sometimes that happens on well used guns, other times it's art of it's design to use that type of tappet.

Your gun sounds mostly up to speed, but here's something I found with one of my TM MP5s: Had misfires, and double feeding on semi, couldn't figure it out, until I found two things. I had put the front part of the hop up unit, the horseshoe with the ledge on backwards, and also had a stripped thread on one side of it where the screw mates. The two together caused my inner barrel to slip forward enough to cause the problems, yet looking at it all seemed everything was fine. Once I put the horseshoe in the other way,with the ledge facing the hop up unit, and fixed the hop up side threads, that fixed it.

Case in point, look closer with the new info in mind. Might fix, might be a waste of calories checking it. At least it eliminates a possibility, one way or another.

[Styrak]

Originally Posted by mongo007

nearest gundoc is 3 hrs away for me

You can always ship it to someone.

[Reckless]

shimming of the gear that engages the tappet plate? ... I've seen them have enough "up and down" movement in their shimming that the gear "nub" actually goes under the tappet after a partial pull back.